1. Field of the Invention
The present invention relates to shoring assemblies, such as vertical shoring assemblies, that support the sides of an excavation and which are designed to prevent cave-ins.
2. Background of the Related Art
It is common practice to shore or support the walls of an excavation (i.e., a trench) with one or more shoring systems. It is well known in the art of shoring to employ collapsible hydraulic shoring systems which are adapted for repeated use. FIG. 1 depicts a plurality of typical shoring systems 10, commonly known in the art as a vertical shores, used in parallel to support the walls W of an excavation. Each of the shoring systems includes a pair of aluminum rails (also known in the art as uprights) 12 suitable for abutting the walls W of the excavation and providing the support desired. The rails 12 are shown spaced apart by a pair of hydraulic jacks (also known in the art as crossbraces) 14 which are pivotally attached to the rails so as to permit the system 10 to be selectively collapsed and expanded by pivoting the jacks and folding rails 12 towards each other.
Such folding action permits shoring systems 10 to be placed within an excavation, and removed therefrom, without the need for an operator to be inside the excavation. As shown in FIG. 2A, the placement sequence includes connecting the system 10 to a portable pumping unit 16 via a hydraulic line 18, and lowering the connected system 10 into the excavation between walls W (left diagram) using ropes 22. The shoring system 10 is then permitted to unfold under its own weight (center diagram), and the pumping unit 16 is activated to achieve a suitable operating pressure in the hydraulic jacks 14 (typically, 750-1500 psig) thereby generating the support force provided through the rails 12 against the walls W (right diagram).
The removal sequence is generally depicted in FIG. 2B, and includes discharging the hydraulic fluid, which is biodegradable, from the system 10 to depressurize the jacks 14, and retracting the system 10 using ropes 22 to fold the rails 12 towards one another (left and center diagrams). The shoring system 10 is then carried away by the operator (right diagram).
The hydraulic jacks 14 are pivotally attached to the rails using force-transmitting pads (also called blocks), as shown in FIG. 3. More particularly, pads 24, commonly known as cylinder pads, are affixed to hydraulic cylinders 28 of hydraulic jacks 14 and are pivotally connected to cylinder rail 12a using pins 30a. Pads 26, commonly known as socket pads, are operatively connected to hydraulic rams or piston rods 32, via an oversleeve 35, and are pivotally connected to socket rail 12b using pins 30b. The hydraulic cylinders are fluidly interconnected by hydraulic line 40 and couplings 34, 36 secured in respective complementing ports (not numbered) of the cylinder pads 24. This interconnection permits both of the hydraulic jacks 14 to be pressurized and/or discharged through a single valve, such as a quick-connect valve 38.
A notable shortcoming in conventional shoring systems is the absence of a means for securing the rails 12 when folded together for transport. This creates a risk that the rails will separate (under the weight of the “lower” rail and the jack assembly) while being carried, resulting in uncontrolled dropping of the lower rail and pivoting of the hydraulic jacks 14. Such uncontrolled movement presents a hazard to the operator carrying the shoring assembly—particularly in the “pinch zones” 200 (see FIG. 3)—that may result in serious injury. A need therefore exists for restricting movement of the rails of a shoring assembly from the closed or folded position.